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Stunning Neanderthal discovery explains a big mystery

Scientists have cracked the mystery of why we don't have more Neanderthal DNA.

A new study is shining the light on the relationship between Neanderthals and modern humans — or lack thereof.

Modern humans have a little bit of DNA from Neanderthals, indicating that we likely interbred with them at some point in our history, but there isn’t much DNA there — and scientists have figured out why, according to a Cell Press statement.

Scientists have determined that the Y chromosome would have created conditions that would have led to miscarriages when the two species interbred.

Neanderthals died out about 40,000 years ago and lived predominantly in Europe and Asia. The Neanderthal genome was first sequenced back in 2010, revealing that there was interbreeding with humans.

But the Y chromosome, which determines what gender a child is going to be, might be the reason why we don’t find more than trace amounts of Neanderthal DNA in ours. The Neanderthal Y chromosome is distinct from that of modern humans, and can trigger immune responses during pregnancy that can result in miscarriages.

“Characterizing the Neanderthal Y chromosome helps us to better understand the population divergence that led to Neanderthals and modern humans,” Fernando Mendez of Stanford University said in the statement. “It also enables us to explore possible genetic interactions between archaic and modern [gene] variants within hybrid offspring.”

The statement adds: “The researchers say that the Neanderthal Y chromosome they sequenced is distinct from any Y chromosome observed in modern humans, suggesting that the lineage in question is to be extinct. They also found some intriguing protein-coding differences between genes on the Neanderthal and modern human Y chromosomes.”

“The finding that most of the functional differences associate with these genes, rather than with genes involved in [sperm production], came as a surprise,” Mendez said.